The energy of an x-ray beam hitting a generally flat detector will not be converted completely into an electrical signal at the contact point (x, y: Cartesian coordinates of the contact point) and at the locations lying directly beneath it with the same lateral coordinates (x, y). The scintillation process generates electrical signals in adjacent locations and even in locations further away. I.e. an x-ray beam which hits a pixel with the coordinates (x, y), generates electrical signals in the contacted pixel, in the surrounding pixels and even in pixels further away. This non-locality of the energy conversion leads to image smear and thus to reductions in contrast.